2 Chronicles 20:20-21

They were up early in the morning, ready to march into the wilderness of Tekoa. As they were leaving, Jehoshaphat stood up and said, “Listen Judah and Jerusalem! Listen to what I have to say! Believe firmly in GOD, your God, and your lives will be firm! Believe in your prophets and you’ll come out on top!” After talking it over with the people, Jehoshaphat appointed a choir for GOD; dressed in holy robes, they were to march ahead of the troops, singing